- Fixed the Tank's primary attack sometimes choosing different sequences between the client and server. Fixes hit traces not always matching the visible animation.- Fixed the Tank's left-handed attack using the right hand's position for hit traces.- Player-controlled Tanks now always choose the right arm horizontal swing sequence for primary attacks. Fixes some attacks not connecting when it appears they should have, due to the inability to predict which swing animation would be randomly chosen.

- Fixed the game and tools not launching on machines with 16+ CPUs.- Fixed missing and incorrect music being played in the L4D1 campaigns- Swamp Fever - The Swamp: Added additional self-terminating survivor-only blockers to the areas above the airplane wreckage to prevent players from skipping the airplane event. These blockers are killed once the airplane door is opened.- Cold Stream South Pine Stream: Added a small blocker next to a crate near the military truck near mid-level to resolve a minor stuck spot.- Fixed controller navigation in mutation menus

- Enable controller navigation of menus to support Big Picture mode.- Allow client menus to execute restricted client commands.- Fixed special infected not catching fire if they were already burning from incendiary ammo.- Hunter and Jockey won't be killed if slashed mid-leap by another infected.- Infected damage applied to a Jockey rider is ignored for the Jockey and no longer passed on to the Survivor. This fixes Jockey victims being subject to double damage from infected attacks and instant incap from Tanks.- Tweaked boss zombie spawn timing in Versus to prevent the Tank spawning as soon as the Survivors exit the safe room.- Fixed the first maps in Dead Center and Swamp Fever not using the boss spawning rules for starting maps, which are more restrictive than other maps.

- Added new startup and connect warnings if the player has -insecure in the launch options- Protected against a crash in infected ragdolls- Added fallbacks to common infected spawning to prevent a common crash when population data is missing- Fixed a bug that allowed malicious servers to execute restricted console commands on players- Fixed a bug that allowed malicious servers to prevent players from executing console commands- Fixed incorrect "Survivors Have Escaped" state for Player Infected when a scripted crescendo event is played after a successful finale escape.- Update to Confogl mutation to fix a possible crash on team swap- If you are receiving an "Error 55" while connecting to dedicated servers, please make sure to accept the Steam Beta update then restart Steam.

Updates to Left 4 Dead 2 have been released. The updates will be applied automatically when your Steam client is restarted. The major changes include:

- Console commands update_addon_paths and unload_all_addons can't be used while connected to a server.- Some custom UI's give the ability to change which add-ons are active from the in-game menu. Now those changes won't be applied until the player returns to the lobby or main menu.- Melee weapon scripts can optionally define the HUD icon data inside the script, similar to other weapons. See golfclub.txt for a format sample.- Fixed a rare crash in the Spitter attack.- Fixed a rare crash in bot navigation involving ladders.